Radio Transcript

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Atmospheric scientist, Dr Warwick Grace, is working with the South Australian Research and Development Institute Climate Applications Unit (otherwise known as the SARDI Climate Applications Unit) so that he can gain a better understanding of heat waves in the Riverland and other wine growing regions of South Australia.

Dr Grace has developed what is believed to be the first heat wave occurrence model.  This is based on records from all over the State dating back more than 100 years, and statistics from the past 30 years collected at the SA Bureau of Meteorology’s Kent Town office.

Dr Grace tells us that “This heat wave is close to being off the scale. It is an extraordinary event with a .03% chance of occurring the odds are about the same as tossing 12 coins and getting all heads or all tails,”

Dr Grace has modelled data for Adelaide, Nuriootpa, Loxton and the Coonawarra.

The results are fascinating “Adelaide, with 15 days over 35 degrees, returns a one in 3000 year event,
while Nuriootpa with 13 days over 35 degrees is a one in 1000 year event, Loxton with 15 days over 35 degrees is a one in 200 year event, and the Coonawarra with five days over 35 degrees is a one in 10 year event.”

SARDI Climate Applications Unit leader, Dr Peter Hayman, says Dr Grace’s work is very valuable in characterising the climate of different regions  and the likelihood and duration of heat waves they might face in the current climate and future climates.

Dr Hayman explained
In the past the emphasis has been on changes in average temperatures, characterising for example a whole summer as being warmer or cooler.

This summer, based on average temperatures, will be rated as a cooler summer overall despite this extraordinary heat wave.  So we have to consider these extreme events and better understand the weather patterns that cause them, and how we can manage them in the vineyard.”

The information from Dr Grace’s research will feed into projects funded by the Grape and Wine Research and Development Corporation and the Centre for Natural Resource Management to help growers manage risk in dealing with climate variability.

One project that will particularly benefit is looking at heat stress on vines. In order to understand viticulture ‘thresh-holds’.

Vines are being tested at critical growing periods in purpose built heat-stress tents to artificially increase canopy and bunch temperatures by up to 10 degrees above the norm.  Ultimately the SARDI team hopes to find a way to use predictions from the Bureau of Meteorology which indicate a high risk of heat stress so that they can try to ensure minimal losses by identifying when growers must prepare – perhaps through canopy management or altering their irrigation regimes.

For further information on this story or any edition of Agritalk, please visit www.ruralsolutions.sa.gov.au, click on news, then radio.  You will find a transcript of the program along with lots of handy links to the things discussed.

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